Preparing for the unprecedented – Moving towards quantitative understanding of oil spill impacts on Arctic marine biota
Year: 2019
Type: dissertation
Abstract: The risk of a major oil spill in the Arctic has become a matter of global concern, since climate change is extending the ice-free period and bringing more shipping to the area. The Arctic is already under great pressure from climate change, and an oil spill in this unique and sensitive environment could be a catastrophe for its biota. Fortunately, no major oil spill has happened in the true Arctic yet, but as the probability of one is increasing, we need to prepare for the potential consequences. Understanding the likely impacts of Arctic oil spills could greatly benefit conservation of the area as, for example, spatially and temporally varying risk could be taken into account when selecting shipping routes. Hence, comprehensive knowledge about the impacts of oil spills on Arctic ecosystems is needed. So far, however, knowledge about the likely impacts of oil on Arctic biota is scarce and insufficient for comprehensive risk assessment. The thesis constructs and applies a probabilistic framework for assessing the environmental risk oil spills pose for marine biota in the data-poor Arctic. The work consists of the summary and four research papers. Paper I brings together the current understanding about Arctic oil spills and their environmental impacts, and conceptualizes that knowledge as a probability-based framework that can guide further risk assessment. It further identifies the key Arctic marine functional groups that environmental risk assessment should focus on. Paper II carries out an expert elicitation to quantify the acute oil spill -induced mortality of adult and offspring individuals belonging to each functional group. Paper III develops a vulnerability index describing the acute mortality and the longer-term recovery potential of the functional groups based on scientific and grey literature. Paper IV uses the information collected in papers I–III and combines it with estimates of oil spreading and species distributions to compare the spatiotemporally varying mortality risk for polar bears, ringed seals and walrus in a case study area, the Kara Sea. The results of the thesis suggest that, in general, polar bears and marine birds are most at risk from spilled oil in the Arctic, but there is great variation in the risk depending on the timing of the spill and the type of oil spilled. Moreover, the distribution of biota in relation to shipping routes can have a major impact on the risk the spilled oil poses to them. Furthermore, the amount of ice present at the spill site can alter the risk to biota, as ice cover affects both the spreading of oil and the abundance of species in the vicinity of the oil spill. On an acute scale, medium density oil spilled when ice concentration are relatively low seems to be the worst-case accident scenario when considering the joint impact on all biota, but determining the safest shipping route may prove to be challenging. This thesis offers new insights into the risk that oil spills pose to Arctic biota, and is a step on the way towards a comprehensive understanding of the impact of Arctic oil spills. However, there are still great knowledge gaps, which this thesis both identifies and aims to minimize by suggesting different methods for efficient data collection to benefit risk management related to Arctic shipping. Additional research is needed to evaluate the longer-term impacts of spilled oil and the persistence of oil in cold environments in particular. Furthermore, the need for a valuing method to guide both risk assessment and management is recognized.
Source: Työväentutkimus Vuosikirja
Author: Maisa Nevalainen
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: green
OpenAlex ID: W2953595654